Key result
The interacting-heads motif has been conserved as a mechanism of myosin II inhibition since before the origin of animals, highlighting its importance in regulating the relaxed state of myosin.
The interacting-heads motif, which regulates myosin II activity by inhibiting it in relaxed muscle and nonmuscle cells, has been conserved as a regulatory mechanism since before the origin of animals.
Answers are grounded in this paper and cite their sources.
Deep evolutionary conservation of myosin II inhibition warrants mechanistic study in muscle; leaves open therapeutic targeting in human cardiac disease.
Significance All animals have the ability to move. Myosin II is the motor protein that generates this movement by powering muscular contraction; it also drives motility in nonmuscle cells. In relaxed muscle and in quiescent nonmuscle cells, myosin II is switched off by intramolecular interactions between its heads that inhibit its activity. This interacting-heads motif (IHM) is a fundamental contributor to contractile regulation. Given its importance in cell contractility, we wanted to determine when the IHM first evolved. Using electron microscopy, image averaging, and sequence analysis of myosin II from primitive organisms, we show that the IHM has existed since the earliest animals and before. This ancient origin highlights the central role of the IHM in regulating myosin II function.
No takes yet. Share an insight, caveat, or question.
Lee et al. (2018) studied this question. The interacting-heads motif has been conserved as a mechanism of myosin II inhibition since before the origin of animals, highlighting its importance in regulating the relaxed state of myosin.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: